Apparatus for recording respiratory sounds in exercising horses

ABSTRACT

A portable recording unit ( 10 ) for recording the upper airway respiratory sounds of an exercising horse to determine whether the horse suffers from an upper airway obstruction condition. The portable recording unit ( 10 ) comprises horse restraining apparatus ( 200 ) wherein microphone ( 12 ) is mounted on support ( 14 ), which is secured to nose-band ( 202 ) of horse restraining apparatus ( 200 ), and recorder ( 16 ). When horse restraining apparatus ( 200 ) is mounted onto head ( 102 ) of horse ( 100 ), microphone ( 12 ) is positioned forward to and between nostrils ( 108 ) of horse ( 100 ). Recorder ( 16 ) is fastened to neck ( 104 ) of horse ( 100 ) or is located at a remote location. Portable recording unit ( 10 ) allows recording of the upper airway respiratory sounds made by the exercising horse ( 100 ).

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Provisional Application Serial No.60/285,985, filed Apr. 24, 2001.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A “COMPUTER LISTING APPENDIX SUBMITTED ON A COMPACT DISC”

Not applicable.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to an apparatus for recording the upperairway respiratory sounds of a horse during exercise of the horse todetermine whether the horse suffers from an upper airway obstructioncondition. In particular, the present invention relates to an apparatuscomprising a horse restraining apparatus with a support member thereonwhich positions a microphone forward to and between (adjacent to) thehorse's nostrils to detect respiratory sounds of the horse duringexercise and which transmits the detected respiratory sounds to arecorder for analysis.

(2) Description of Related Art

Horses commonly suffer from several different upper airway obstructivediseases (conditions), including left laryngeal hemiplegia (LLH), dorsaldisplacement of the soft palate (DDSP), pharyngeal collapse, andentrapment of the epiglottis. Left laryngeal hemiplegia and DDSP are byfar the most common causes of upper airway obstructions in horses andthese conditions have an estimated prevalence of approximately 10% ofhorses. Left laryngeal hemiplegia is caused by a neuropathy of the leftrecurrent laryngeal nerve. This condition results in the paresis of theassociated arytenoid cartilage. During exercise, this cartilage causesairway obstruction, respiratory noise, and exercise intolerance(Seeherman, In: Current Therapy in Equine Medicine 4. Robinson (ed), W.B. Saunders, Philadelphia, pp. 404-407 (1997)).

The cause of dorsal displacement of the soft palate is presentlyunknown. Experimentally, the disease is reproduced by blockade of thepharyngeal branch of the vagus nerve. Because this nerve branch runs inclose proximity to the retropharyngeal lymph nodes, it is thought thatin naturally occurring cases, DDSP is caused by infection of these lymphnodes and consequent damage to the nerve branch. Like in cases with LLH,DDSP causes airway obstruction, respiratory noise production andexercise intolerance in affected horses (Ducharme et al., In: CurrentTherapy in Equine Medicine 4. Robinson (ed), W. B. Saunders,Philadelphia, pp. 415-418 (1997)). In many cases, upper airwayconditions can not be diagnosed in the resting horse as the conditionsonly occur during exercise. Upper airway obstructions are oftenassociated with abnormal respiratory noise.

Respiratory sounds in exercising horses are difficult to evaluatebecause the trained observer is not always in an optimal location tohear the respiratory sounds. Furthermore, the respiratory sounds areobscured by extraneous noises such as hoof beats, wind noise, or soundsassociated with treadmill operation. Presently, diagnostic methods aretime consuming, highly technical, and expensive. The old method ofdiagnosing upper airway conditions in horses involves fiber opticendoscopy. In this technique, a fiber optic endoscope is inserted in thehorse's nose and observations are made. To diagnose upper airwayconditions that are only apparent during exercise, the horse isexercised on a high-speed treadmill and endoscopy is performed duringexercise. This method is highly technical and can only be performed inreferral centers.

In human medicine, spectrogram analysis of speech is a large field ofstudy and practical applications of this field, including speech therapyand voice recognition, are now commonplace (Kent, J. Voice 7: 97-117(1993)). In addition, spectrogram analysis of sound has been used inmany animal species, including songbirds (Lindell, Wilson Bull. 110:368-374 (1998)) and marine mammals (Hanggi and Schusterman, Anim. Behav.48: 1275-1283 (1994)).

Respiratory sounds of horses have been recorded using a radiostethoscopesuch as that disclosed by Attenburrow et al., in Equine Exerc.Physiol._(—): 27-32 (1990) and in U.S. Pat. No. 4,218,584 to Attenburrowboth of which describe a stethoscope for detecting and recording datafrom a horse while the horse is walking, trotting, cantering, jumping,and galloping. The invention includes a transducer, such as a microphonewhich is attached to the animal's skin adjacent the windpipe. Theelectrical output from the transducer is transferred to a radiotransmitter mounted on the animal or its harness. The radio transmittercan transmit signals a distance from the horse to allow for monitoringthe horse's breathing from a distance. While the respiratory soundsdetected by the radiostethoscope placed over the trachea are analyzedusing spectrogram analysis, the respiratory sounds do not directlyrelate to the respiratory sounds of exercising horses.

To correlate the respiratory sounds recorded by the radiostethoscope toinspiration or expiration of the exercising horse, Attenburrow in EquineVet. J. 10: 176-179 (1978) further suspended a sub-miniature microphonejust in front of one nostril. The microphone detects expiration by usingthe blast effect made by expired air upon the suspended microphone. Theblast effect is the sound made by rushing expired air hitting themicrophone which sounds much like the sound made by a strong windhitting a microphone at an outdoor concert. Thus, the microphone is notdetecting actual upper airway respiratory sounds made by the horseduring respiration. Therefore, when a blast effect is detected by themicrophone, the corresponding respiratory sound detected by theradiostethoscope was made during expiration. Conversely, when a blasteffect is not detected by the microphone, the respiratory sound detectedby the radiostethoscope was made during inspiration.

Also, of interest is U.S. Pat. No. 4,720,866 to Elias et al. whichdescribes a method and apparatus for acquiring, analyzing, anddisplaying stethoscopic data using a microcomputer. The stethoscopicdata come from lung sounds, not upper airway sounds as recorded in theinvention described therein. The invention includes a means forproviding an audio signal. The audio signal is pre-amplified andconditioned for application to a bank of fixed-center-frequencyelectronic filters. The output of each filter is sampled and convertedto digital form. The output is then processed in a computer for analysisand display on a CRT screen or recording in a hard copy device.

U.S. Pat. No. 5,165,417 to Murphy, Jr. describes a diagnostic method andapparatus for detecting breathing abnormalities in humans to diagnoselung (not upper airway) disorders. The system includes means forreceiving the sound signal from the patient, means for conditioning thesound signal to attenuate normal sounds, and means for storing a samplesound signal. The system may also include means for digitizing the soundsignal, means for amplifying the sound signal, means for determining anaverage signal value of at least a portion of the sound signal, andmeans for generating a threshold value based on that average value.Further included may be means for sequentially comparing the sound waveswith the predetermined time interval to identify an initial deflectionwave having a duration falling within the time interval, meansresponsive to the means for sequentially comparing the sound waves forsequentially comparing the sound waves following the initial deflectionwave to the threshold value, and means for identifying an adventitioussound occurring within the sound signal only when a plurality ofconsecutive sound waves including the initial deflection wave have anamplitude at least as large as the threshold value.

U.S. Pat. No. 5,737,429 to Lee describes a portable, visible, andaudible stethoscope. The stethoscope includes a sound absorbing cuphaving a microphone and an output device. In use, the sounds from thehuman body are converted into electrical signals by microphone. Theelectrical signals are amplified in the output device and supplied tothe speaker of the output device to produce an audio signal. Theamplified electrical signals are also supplied to the oscilloscope toproduce a graph representing the electrical signals.

Only of minimal interest is U.S. Pat. No. 5,503,141 to Kettl et al.which shows a microphone mounting structure which permits conversion ofa conventional respirator into a sound amplifying respirator. Theinvention uses a microphone responsive to oral sounds within therespiratory mask and produces electrical signals indicative of theseoral sounds. The system also includes an amplification circuit whichprovides output sounds representative of the oral sounds which themicrophone detects within the mask.

In light of the prior art, there remains a need for an apparatus forrecording the upper airway respiratory sounds of a horse during exercisewhich is portable and easy to use and which allows the recordedrespiratory sounds to be analyzed for upper airway obstructive diseases.

SUMMARY OF THE INVENTION

The present invention provides an apparatus for recording the upperairway respiratory sounds of a horse during exercise which is portableand easy to use and which allows the recorded respiratory sounds to beanalyzed for upper airway obstructive diseases either after exercise orin real time.

In particular, the present invention provides an apparatus for recordingrespiratory sounds of an exercising horse which comprises (a) amicrophone with a head which detects respiratory sounds at closeproximity; (b) a horse restraining apparatus comprising a nose-band anda cheek-piece with a top for going behind and around the ears of thehorse both mountable on the head of the horse wherein the horserestraining apparatus includes a support means for the microphonemounted on the nose-band of the horse restraining apparatus wherein thesupport means allows the head of the microphone to be positioned betweennostrils of the horse without touching the horse so that the respiratorysounds at close proximity to the nostrils of the horse are detected; and(c) a recording means for recording the respiratory sounds from themicrophone at close proximity to the nostrils of the horse wherein therecording means squelches other sounds at a distance from the nostrils.

In a further embodiment of the apparatus, a wire for transmitting therespiratory sounds detected by the microphone to the recording meansextends from the microphone to the recording means along a path which isparallel to the support means mounted on the nose-band of the horserestraining apparatus and is parallel to the nose-band and thecheek-piece to the top of the cheek-piece and which extends from the toppiece to the recording means.

In a further embodiment of the apparatus, the support means is a tubedefined by at least one wall forming the tube in which the wire fortransmitting the respiratory sounds extends therethrough.

In a further still embodiment of the apparatus, the microphone isunidirectional.

In a further still embodiment of the apparatus, the recording means hasa compression circuit which allows for a constant recording level of thesounds at close proximity to the nostrils of the horse.

In a further still embodiment of the apparatus, the microphone includesa wireless transmitter for transmitting the respiratory sounds to awireless receiver in the recording means.

In a further still embodiment of the apparatus, the microphone includesa wireless transmitter for transmitting the respiratory sounds to awireless receiver in a computer for analyzing the respiratory sounds inreal time.

The present invention further provides a method for recording andanalyzing respiratory sounds of an exercising horse to detect an airwaycondition which comprises (a) providing an apparatus for analyzingrespiratory sounds of an exercising horse which comprises (1) amicrophone with a head which detects respiratory sounds at closeproximity; (2) a horse restraining apparatus comprising a nose-band anda cheek-piece with a top for going behind and around the ears of thehorse both mountable on the head of the horse wherein the horserestraining apparatus includes a support means for the microphonemounted on the nose-band of the horse restraining apparatus wherein thesupport means allows the head of the microphone to be positioned betweennostrils of the horse without touching the horse so that the respiratorysounds at close proximity to the nostrils of the horse are detected; and(3) a recording means for recording the respiratory sounds from themicrophone at close proximity to the nostrils of the horse and squelchesother sounds at a distance from the nostrils; (b) mounting the head ofthe microphone adjacent to the nostrils of the horse; (c) recording therespiratory sounds detected by the head of the microphone with therecording means; and (d) analyzing the respiratory sounds recorded onthe recording means to detect the condition.

In a further embodiment of the method, a wire for transmitting therespiratory sounds detected by the microphone to the recording meansextends from the microphone to the recording means along a path which isparallel to the support means mounted on the nose-band of the horserestraining apparatus and is parallel to the nose-band and thecheek-piece to the top of the cheek-piece and which extends from the toppiece to the recording means.

In a further still embodiment of the method, the support means is a tubedefined by at least one wall forming the tube in which the wire fortransmitting the respiratory sounds extends therethrough.

In a further still embodiment of the method, the microphone includes awireless transmitter for transmitting the respiratory sounds to awireless receiver in the recording means.

In a further still embodiment of the method, the microphone includes awireless transmitter for transmitting the respiratory sounds to awireless receiver in a computer for analyzing the respiratory sounds inreal time.

In a further still embodiment of the method, the analysis is forlaryngeal hemiplegia and dorsal displacement of the soft palate.

In a further still embodiment of the method, a computer program producesa graph of the respiratory sounds for analyzing in step (d).

The object of the present invention is to provide an easy andinexpensive method and apparatus for diagnosing upper airway obstructionconditions in exercising horses.

That and other objects of the present invention will become increasinglyapparent with reference to the following drawings and examples ofembodiments which satisfy the objects of the present invention.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of the portable recording unit 10 comprising horserestraining apparatus 200 with microphone 12 and support 14 secured tonose-band 202 of horse restraining apparatus 200.

FIG. 2 is an overhead view of horse 100 with portable recording unit 10mounted on the head 102 thereof. The Figure shows that microphone 12 ispositioned forward and between the nostrils 108 of the horse 100 so asto be outside the path of the air 50 expired from the horse's nostrils108.

FIG. 3A shows a right-side view of the portable recording unit 10comprising horse restraining apparatus 200.

FIG. 3B shows a left-side view of the portable recording unit 10comprising horse restraining apparatus 200.

FIG. 4 shows the section of the nose-band 202 to which the support 14 issecured with bracket 17 and cheek-piece 204 of the horse restrainingapparatus 200.

FIG. 5 shows a perspective view of the horse 100 exercising on atreadmill 110 with the respiratory sounds monitored by portablerecording unit 10 comprising wireless microphone 412 and wirelessrecorder 416.

FIG. 6 shows a cross-section view of support 14 viewed along line 6 ofFIG. 4 showing sidewall 330 defining internal space 332 and wire 20.

FIG. 7 shows wireless microphone 412 comprising microphone 12 secured tothe distal end 13 of support 14 wherein the microphone 12 is operablyconnected by wire 20 to transmitter 400 and wireless recorder 416comprising recorder 16 operably connected to receiver 500 by wire 20.

FIG. 8A shows a cross-section view of a two-piece nose-band 302 as itwould appear if viewed along line 8A of FIG. 4.

FIG. 8B shows a cross-section perspective view of a two-piece nose-band302 as it would appear if viewed along line 8B of FIG. 4.

FIG. 8C shows a cross-section perspective view of a two-piececheek-piece 304 as it would appear if viewed along line 8C of FIG. 4.

FIG. 9 shows a spectrogram of the upper respiratory sounds of a horse100 with left laryngeal hemiplegia (LLH) exercising on a treadmill 110at a speed corresponding to its maximum heart rate.

FIG. 10 shows a spectrogram of the upper respiratory sounds of a horse100 with dorsal displacement of the soft palate (DDSP) exercising on atreadmill 110 at a speed corresponding to its maximum heart rate.

FIG. 11 shows a spectrogram of the upper respiratory sounds of a normalhorse 100 exercising on a treadmill 110 at a speed corresponding to itsmaximum heart rate.

DETAILED DESCRIPTION OF THE INVENTION

All patents, patent applications, government publications, governmentregulations, and literature references cited in this specification arehereby incorporated herein by reference in their entirety. In case ofconflict, the present description, including definitions, will control.

During exercise, horses make upper airway respiratory sounds(hereinafter, “respiratory sounds”). In horses with different airwayobstruction conditions, these upper airway respiratory sounds change andimportantly, these changes in upper airway respiratory sounds arecharacteristic for each upper airway obstruction condition. The portablerecording unit of the present invention comprises a horse restrainingapparatus which comprises a nose-band and a cheek-piece with a top forgoing around and behind the ears of the horse to keep the nose-band fromslipping off the nose (a preferred horse restraining apparatus is acavesson), a microphone (preferably unidirectional) secured to a supportwhich is mounted on the nose-band, and a recorder (preferably withcompression circuitry). The portable recording unit of the presentinvention provides an easy and inexpensive method and apparatus fordiagnosing upper airway obstruction conditions in exercising horses. Theportable recording unit of the present invention is an improvement overthe portable recording unit taught in commonly owned U.S. Pat. No.6,228,037 to Derksen.

Shown in FIGS. 1 and 2 is an embodiment of the portable recording unit10 which comprises a horse restraining apparatus 200 (the Figure shows acavesson, which is the preferred horse restraining apparatus), amicrophone 12 (preferably unidirectional), and a recorder 16 (preferablywith compression circuitry). The combination of a unidirectionalmicrophone and the compression circuitry filters out extraneous noisessuch as hoof beats, wind noise, and sounds associated with treadmilloperation.

The horse restraining apparatus 200 comprises a nose-band 202 and acheek-piece 204 with a top 206. The top 206 of the cheek-piece 204 andis formed when the cheek-piece 204 is fitted around the head 102 of thehorse 100 and secured with buckle 210 (FIG. 3A). The microphone 12 issecured to the distal end 13 of a flexible or bendable support 14,preferably the support 14 is a flexible or bendable conduit. Theproximal end 15 of the bendable support is secured to nose-band 202 ofthe horse restraining apparatus 200 by bracket 17.

In a preferred embodiment, the horse restraining apparatus is acavesson. Traditionally, cavessons are made from leather, however, nyloncavessons are also available. A cavesson may or may not have a metalnose-band. The recording unit 10 can comprise any manufacture ofcavesson. Furthermore, while a cavesson is shown in the Figures, oneskilled in the art will readily appreciate that a bridle or halter witha nose-band can be substituted for or combined with the cavesson withoutdeparting from the spirit of the present invention. Therefore, the term“horse restraining apparatus” as used herein includes leather, nylon,metal nose-band, lungeing, and bitting cavessons and other horserestraining equipment such as bridles, bitless bridles, halters, and thelike so long as the horse restraining apparatus has a nose band to whichthe support 14 can be mounted and a cheek-piece that goes around thehorse's ears as shown in the Figures to keep the nose-band from slidingoff the nose.

In the embodiment shown, the support 14 is a flexible or bendableconduit and the microphone 12 is operably connected to recorder 16 bywire 20. The wire 20 travels from the microphone 12 through the flexibleor bendable support 14 (FIG. 6 shows a cross-section view of the support14 showing inner space 332 for wire 20 to travel through) and then exitsthe support 14 at its proximal end 15 wherein it then travels along apathway parallel the nose-band 202 to the cheek-piece 204 and then alonga pathway parallel the cheek-piece 204 to the top 206 wherein it thentravels along the neck 104 of the horse 100 to the recorder 16. The wireis fastened to nose-band 202 and cheek-piece 204 by a plurality offastening means 212 such as stitching, clamps, tacks, adhesive, or thelike.

As shown by FIGS. 1 and 2, when the recording unit 10 is mounted on thehead 102 of the horse 100, the microphone 12 of the portable recordingunit 10 is positioned by the support 14 to be adjacent the horse'snostrils 108, i.e., forward of the horse's nose 106 and between thehorse's nostrils 108, and the recorder 16 is mounted on the neck 104 ofthe horse 100. The microphone 12 and the recorder 16 can be analog,digital, or combination thereof.

To position the microphone 12 forward to and between the nostrils 108 ofthe horse 100, i.e., adjacent to the nostrils 108, the microphone 12 issecured to the distal end 13 of the support 14 Preferably, themicrophone 12 and the support 14 are a single unit. The microphone 12 ispositioned such that the head 12A of the microphone 12 extends inwardtoward the proximal end 15 of the support 14. The proximal end 15 of thesupport 14 is then secured to the nose-band 202 of the horse restrainingapparatus 200 by bracket 17 which is in turn secured to the nose-band202 by a securing means 218 such as bolts, rivets, tacks, stitching,adhesive, or the like (FIG. 4).

In particular embodiments, the support 14 or the proximal end 15 of thesupport 14 is metal which enables the support 14 to be secured to thebracket 17 by welding. In other embodiments, the support 14 is securedat the proximal end 15 by bracket 17 wherein the bracket 17 tightlyclamps the proximal end 15 of the support 14 to the nose-band 202.

The horse restraining apparatus 200 is then mounted on the head 102 ofthe horse 100 such that the support 14 is cantilevered over the nose 106of the horse 100 and extended beyond the nose 106 a sufficient distanceto place the microphone head 12A of microphone 12 at the distal end 13of the support 14 in front of the nose 106 and between the nostrils 108.The proximal end 15 of the support 14 is secured to horse restrainingapparatus 200 with the bracket 17.

An important element of the recording unit 10 is illustrated in FIG. 2.As shown in FIG. 2, the microphone 12 is positioned such that while thehead 12A of the microphone 12 is in close proximity to the nostrils 108of the horse 100 to enable it to detect the horse's respiratory sounds,it is not directly in front of either nostril 108 of the horse 100. Themicrophone 12 is not directly in front of either nostril 108 to preventthe microphone head 12A from detecting a blast effect which would resultif the expired air 50 from the nostrils 108 of the horse 100 were tocontact the microphone head 12A. The blast effect would interfere withdetecting the respiratory sounds. In contrast, Attenburrow in EquineVet. J. 10: 176-179 (1978) places a microphone directly in front of anostril for the sole purpose of detecting the blast effect which is thenused to determine whether the respiratory sounds detected by theradiostethoscope were made during expiration or during inspiration.

FIG. 3A shows a right-side view of the recording unit 10 and FIG. 3Bshows a left-side view of recording unit 10. The Figures show horserestraining apparatus 200 (the Figure shows a cavesson which ispreferred) with nose-band 202 and cheek-piece 204 and top 206. TheFigures show the support 14 with microphone 12 secured to the distal end13 of the support 14 so that the microphone head 12A is facing theproximal end 15 of the support 14 and shows the proximal end 15 of thesupport 14 secured to the nose-band 202 by clamp 17. Exiting from theproximal end 15 of the support 14 is wire 20 which operably connects themicrophone 12 to the recorder 16. Wire 20 is fastened to the nose-band202 and cheek-piece 204 by fastening means 212. The nose-band 202 issecured to the horse's nose 106 using the buckle 208 and the cheek-piece204 is secured to the horse's head 102 using the buckle 210. When thehorse restraining apparatus 200 is fitted to the horse's head with thecheek-piece 204 looped around the horse's head and secured with buckle210, the central section of the cheek-piece 204 forms the top 206. FIG.3B shows that wire 20 travels along a path parallel to the nose-band 202and the cheek-piece 204 and then from the top 206 to the recorder 16.

FIG. 4 shows a close-up view of the support 14 secured to the nose-piece202 of the horse restraining apparatus 200 of the portable recordingunit 10. The Figure shows support 14 with microphone 12 attached todistal end 13 and secured at its proximal end 15 to the nose-band 202 byclamp 17 which is secured to the nose-band 202 with securing means 218.The microphone 12 is positioned such that its head 12A is directedtowards the proximal end 15 of the support 14. Wire 20 exits theproximal end 15 of the support 14 and travels along the nose-band 202and the cheek-piece 204. The wire is secured in place by a plurality offastening means 212.

In particular embodiments not shown, the support 14 can have atelescopic or other slidable construction which allows the length of thesupport 14 to be adjusted. However, it is preferable that the support 14comprise a flexible or bendable conduit. As shown in FIGS. 1 and 2, thebendable or flexible conduit support 14 enables the position of the head12A of the microphone 12 to be adjusted to be just forward of the nose106 of the horse 100 but without touching the nose 106 merely by bendingthe support into the desired position. By positioning the microphonehead 12A just forward of the nose 106, a “tight-mike” technique can beused to record the respiratory sounds at the nostrils 108 of theexercising horse 100. Furthermore, it is preferable that the flexible orbendable conduit be a tube with the wire 20 from the microphone 12traversing therethrough and exiting at the proximal end 15 of thesupport 14. FIG. 6 shows a cross-section of the flexible or bendableconduit support 14 along line 6 of FIG. 4. FIG. 6 shows side wall 330 ofsupport 14 forming a tube with internal space 332 and wire 20 therein.

As shown in FIGS. 1 and 2, the recorder 16 is fastened to the neck 104of the horse 100 by any well known fastening means such as elastic tape,adhesive tape, a belt, or a strap. In this embodiment, since the entirerecording unit 10 is mounted on the horse 100, the test can be performedanywhere the horse 100 can exercise. In a further embodiment, therecorder 16 is fastened to a saddle (not shown) on the back of the horse100, secured in a pocket in the saddle (not shown), a harness (notshown) on the horse 100, a sulky (not shown) pulled by the horse 100, orfastened to the top 206 of the cheek-piece 204. In an alternativeembodiment, the horse 100 is positioned on a high speed treadmill of atype commonly used by veterinarians and horse owners to exercise a horsesuch as the treadmill 110 shown in FIG. 7 and the recorder 16 can beattached to the treadmill 110.

The recording unit of commonly owned U.S. Pat. No. 6,228,037 to Derksenhas a microphone operably connected to a recorder with a wire fortransmitting respiratory sounds received by the microphone to therecorder. The wire hangs along the side of the head of the horse. Inpractice, the hanging wire is distracting to the horse which in turn caneffect the breathing of the horse during recording thereby causingaberrant respiratory sounds. Furthermore, because the hanging wire musthave some slack to allow the horse to move its head naturally duringexercise, the hanging wire will sway to and fro and bounce up and downduring exercise. The swaying and bouncing wire can spook the horse. Thepresent invention solves the hanging wire problem inherent to therecording unit of U.S. Pat. No. 6,228,037 to Derksen.

In the recording unit 10 of the present invention, the wire is anintegral part of the horse restraining apparatus 200. As shown in FIGS.1-4, the wire 20 connecting the microphone 12 to the recorder 16,extends from the microphone 12 through the support 14 to the nose-band202 of the horse restraining apparatus 200. The wire 20 exits thesupport 14 and travels along a path parallel to the nose-band 202 to thecheek-piece 204 of the horse restraining apparatus 200, along a pathparallel to the cheek-piece 204 to the top 206 of the cheek-piece 204 ofthe horse restraining apparatus 200, and then from the top 206 of thecheek-piece 204 to the recorder 16 which is fastened to the neck 104 ofthe horse 100. The wire 20 is fastened to the surface 220 of thenose-band 202 (FIG. 4) and the surface 222 of the cheek-piece 204 (FIG.4) or within a groove or channel (not shown) in the surface 220 and 222of the aforementioned components of the horse restraining apparatus 200.

FIGS. 8A, 8B, and 8C show an embodiment of the recording unit 10 whereinthe nose-band 202 and the cheek-piece 204 of the horse restrainingapparatus 200 comprises two pieces with the wire 20 sandwichedtherebetween. The two-piece construction protects the wire 20 fromdamage. FIG. 8A shows a cross-section view of a two-piece nose-band 302with a top piece 308 and a bottom piece 310 as it would appear if viewedalong line BA of FIG. 4. Between the top piece 308 and the bottom piece310 is bracket 17 securing the proximal end 15 of the support 14 withwire 20 therein. The bracket 17 is shown secured to the bottom piecewith rivets 312 as the securing means 218. FIG. 8B shows the two-piecenose-band 302 with a top piece 308 and a bottom piece 310 with wire 20sandwiched therebetween as it would appear if viewed along line 8B ofFIG. 4. FIG. 8C shows a cross-section perspective view of FIG. 4 of atwo-piece cheek-piece 304 with a top piece 314 and a bottom piece 316with wire 20 sandwiched therebetween as it would appear if viewed alongline 8C of FIG. 4. FIGS. 8B and 8C show the top and bottom pieces heldtogether with stitching 318, however, other means such as adhesive,rivets, tacks, and the like can be used to hold the top and bottompieces together. Both the top and bottom pieces can be made fromleather, nylon, an other material such as rubber, plastic, metal, orcloth, or a combination thereof. For example, the top and bottom piecescan both be made from leather or the bottom piece can be made fromleather and the top piece made from another material such as nylon.

The wire 20 has standard plugs or connectors at both ends (not shown)for plugging the ends of wire 20 into the sockets (not shown) of themicrophone 12 and the recorder 16 to operably connect the microphone 12to the recorder 16. Alternatively, one end of the wire 20 is directlyattached to the circuitry of the microphone 12 (not shown) and the otherend of the wire 20 has a plug (not shown) which is plugged into a socket(not shown) in the recorder 16. As used herein, the term “wire” includesnot only metal wire for electrical transmission of the respiratorysounds but also fiber optic wires for light transmission of therespiratory sounds.

The support 14, which preferably is a flexible or bendable conduit, canbe manufactured from a material which includes but is not limited tometal, metal covered with a plastic, plastic, rubber, reinforced plasticor rubber, or combinations thereof. It is preferable that the support beflexible or bendable such that it can be manually bent into a pluralityof stable configurations. For example, the support 14 is a flexibleconduit comprising a polymeric material which is used to make the boomthat supports the microphone of telephone headsets such as thosecommonly used by telephone marketers and receptionists. It is preferablethat the proximal end of such a support 14 be flanked with a metal coverwhich is then covered with a polymeric material to form a tight bondbetween the flexible conduit and the flanking metal cover (not shown).The metal cover protects the proximal section of the support 14 and canextend the proximal end 15 of the support 14 beyond the proximal end ofthe flexible conduit comprising the support 14. The metal at theproximal end 15 of the support 14 is left exposed to enable the support14 to be welded to the bracket 17 on the nose-band 202.

In a still further embodiment, the transmission of respiratory soundsfrom the microphone 12 to the recorder 16 is by wireless transmission.Wireless transmission can be accomplished by including a wirelesstransmitter operably connected to the microphone 12 to transmit therespiratory sounds and a wireless receiver operably connected to therecorder 16 to receive the respiratory sounds instead of using the wire20 to transmit the respiratory sounds from the microphone 12 to therecorder 16. When a wireless transmitter is used for transmitting therespiratory sounds to a recorder with a wireless receiver therein, therecorder with the wireless receiver therein can be in a location remotefrom the exercising horse 100. Therefore, when respiratory sounds aretransmitted to a recorder by a wireless means, the horse restrainingapparatus 200 need only comprise a microphone with a wirelesstransmitter therein or mounted on the horse and support 14 withmicrophone 12 secured to the nose-band 202.

FIG. 7 shows an embodiment of a wireless microphone 412 comprising amicrophone 12 with head 12A mounted on the distal end 13 of support 14.The microphone 12 is operably connected to a transmitter 400 by wire 20which exits the support 14 at its proximal end 15. Also shown is awireless recorder 416 comprising a recorder 16 operably connected bywire 20 to a receiver 500 which receives the transmissions from thetransmitter.

Wireless transmission of the respiratory sounds enhances the utility ofthe present invention because it eliminates the need for wires and alsoallows for real time analysis of the respiratory sounds as the horse isexercising. Real time analysis enables the exercise regimen to bealtered in response to particular respiratory sounds at the time therespiratory sounds are being made. Thus, while the horse 100 isexercising, the respiratory sounds, which are detected by a microphone12 operably connected to a wireless transmitter, are transmitted to awireless receiver operably connected to a computer comprising a computerprogram for analyzing the respiratory sounds and displaying the resultsof the analyzed respiratory sounds on a computer screen or a printer fora hard copy in real time. Wireless transmission of the respiratorysounds can be by radio, microwave, light, infrared light, ultrasonicsound, or other wireless means.

FIG. 5 shows a wireless embodiment of the recording unit 10 forrecording the respiratory sounds made by a horse while being exercisedon a treadmill. FIG. 5 shows horse 100 on treadmill 110 wherein thehorse 100 has on its head 102 a portable recording unit 10 comprising ahorse restraining apparatus 200 with a wireless microphone 412 as shownin FIG. 7 fastened to nose-band 202 of horse restraining apparatus 200and wireless recorder 416 (with the receiver an integral component ofthe receiver) fastened to treadmill 110 with bracket 18. The wirelesstransmitter 400 is fastened to the neck 104 of the horse 100 and isoperably connected to the microphone 12 by wire 20.

In a further embodiment (not shown), the microphone and recorder orwireless transmitter are of a sufficiently reduced size that both can beattached to the support 14 which is secured to the horse restrainingapparatus 200. In particular embodiments, a single unit comprising botha microphone and a recorder or wireless transmitter is attached to thesupport 14. In further embodiments, the recording unit 10 comprises twomicrophones for detecting respiratory sounds, a microphone for detectingthe respiratory sounds from each nostril 108 of the horse 100, and therecorder contains two channels for recording the respiratory sounds, achannel for each microphone.

In any one of the above embodiments, after the respiratory sounds arerecorded on the recorder and the data transferred to a personal computer(not shown) or transmitted in real time to a recorder containing a radioreceiver and which is operably connected to a computer (not shown) or toa radio receiver operably connected to a computer (not shown), thesounds are analyzed using commercially available spectrum analysiscomputer software. Spectrum analysis allows plotting of time, frequency,and sound amplitude of the respiratory sounds to give easilyrecognizable patterns.

The spectrum analysis patterns associated with various upper airwayobstructive conditions such as left laryngeal hemiplegia (LLH) anddorsal displacement of the soft palate (DDSP) are vastly different. Thespectrogram of the respiratory sounds of a horse with LLH is shown inFIG. 9. The pattern is distinguishable from the spectrogram pattern ofrespiratory sounds of a horse with DDSP as shown in FIG. 10. Both theLLH and the DDSP spectrogram patterns are distinguishable from thespectrogram pattern for the respiratory sounds of a normal horse asshown in FIG. 11. The differences in the respiratory sounds and thecorresponding spectrum analysis patterns are useful for making adiagnosis of a particular upper airway condition in a horse.

Spectrogram analysis of respiratory sounds in exercising horses hasimportant applications. It appears that all of the upper respiratoryconditions of horses are associated with unique spectrogram patterns.Simple recording of respiratory sounds under field conditions can yielda diagnosis of specific upper airway conditions, thereby avoiding theneed for endoscopic examinations on a high-speed treadmill. Also, upperairway conditions in horses are associated with exercise intolerance andrespiratory noise production.

An additional use of the recording unit of the present invention is toevaluate the efficacy of surgical procedures for treating upper airwayconditions. Presently, the efficacy of surgical procedures to treatupper airway conditions is evaluated using measurements of air flows anddriving pressures (Tetens et al., Am. J. Vet. Res. 57: 1668-1673 (1996);Shappell et al., Am. J. Vet. Res. 49: 1760-1765 (1988); Belknap et al.,Am. J. Vet. Res. 51: 1481-1487 (1990)). Changes in respiratory soundsfollowing surgical intervention provides very useful information.

In a series of studies, various surgical techniques for treating theseupper airway conditions were evaluated to determine their ability toreduce upper airway impedance (Tetens et al., Ibid; Shappell et al.,Ibid; Belknap et al., Ibid). However, reduction of upper airwayimpedance in affected horses did not necessarily reduce respiratorynoise. For many owners, the respiratory noise associated with upperairway conditions is just as important as the upper airway obstruction.Spectrogram analysis of respiratory sounds in exercising horses recordedusing any one of the embodiments of the recording unit herein now makesit possible to evaluate the efficacy of surgical techniques in reducingrespiratory sounds associated with upper airway obstructive conditions.

The following example is intended to promote a further understanding ofthe present invention.

EXAMPLE 1

This example illustrates the use of the recording unit 10 (comprisingthe preferred cavesson) for detecting respiratory sounds in horses inwhich LLH and DDSP is experimentally induced.

Horses are studied under baseline conditions and after temporaryinduction of LLH and DDSP using well known local anesthetic techniques(Ehrlich et al., Vet. Surg. 24: 36-48 (1994); Holcombe et al., Am. J.Vet. Res. 59: 504-508 (1998)). Briefly, to induce LLH, 2 cc of localanesthetic is placed over the left recurrent laryngeal nerve as thenerve approaches the larynx. To induce DDSP, 2 cc of local anesthetic isplaced bilaterally over the pharyngeal branches of the vagus nerve asthey run through the guttural pouch. A randomized crossover design isused for the studies. Studies are separated by at least one week. Thespeed at which each horse reaches maximum heart rate is determined usinga rapid incremental exercise test as described in Holcombe et al.(Ibid).

Directly prior to the experiments, the upper airway of each horse isexamined using a fiber optic endoscope to ensure that the upper airwayis functioning normally. Subsequently, the desired experimentalcondition is created (normal, LLH or DDSP) and verified by endoscopicexamination. Next, the portable recording unit 10 is mounted on thehorse 100.

Because the respiratory sounds of interest become manifest only when ahorse 100 is exercising, sound recordings are made while the horse 100is exercising at a speed corresponding to maximum heart rate speedeither in the gallop, trot, or pace. The ambient noise was renderedharmless by two techniques.

First, the recording microphone 12 of the recording unit 10 isunidirectional and when the recording unit 10 is placed on the head 102of the horse, the microphone 12 is preferably about 4.0 cm (1.6 inches)from the tip of the horse's nose 106 (“tight miked”). The microphone 12is centered on the nose 106 between the nostrils 108 and, therefore, isnot in the direct path of the horse's nasal exhalations and is notsubject to blast effect. Nevertheless, the microphone 12 is still inclose enough proximity to the nostrils 108 to detect the respiratorysounds.

The recorder 16 preferably has an automatic gain control. In thisexample, a Panasonic SLIMLINE® Model RQ2102 was used. The PanasonicSLIMLINE® Model RQ2102 recorder is designed for ready recording ofspeech in difficult environments such as conference rooms. The inputsection of the recorder 16 includes a strong compression circuit leadingto a constant recording level that promotes intelligibility. Thecompression system in the recorder 16 is useful because the“tight-miked” exhalations of the horse 100 are intense enough andfrequent enough to activate the recorder's compression feature and tosquelch the ambient noise. The recorder 16 allows for recording therespiratory sounds from the horse 100 while squelching the environmentalnoises associated with the exercising horse 100. The microphone 12 wasattached by the wire 20 to the recorder 16. The recorder 16 is mountedon the horse 100 or alternatively, mounted on a treadmill 110 similar tothat shown in FIG. 5.

Once the portable recording unit 10 is in place, the horses are placedon the treadmill similar to that shown in FIG. 5. After a five minutewarmup period, the horses 100 are exercised at maximum heart rate fortwo minutes. Endoscopic examination is repeated immediately followingthe exercise.

Pharyngeal pressure is measured using a pharyngeal catheter positionedat the level of the guttural pouch openings, as described in Holcombe etal. (Ibid). The pharyngeal pressure is used to determine the timing ofinhalation and exhalation. The microphone 12 and recorder 16 are thenactivated. The respiratory sounds recorded on the recorder 16 are thenanalyzed using a computer based spectrogram program. A software programwhich can be used to analyze the respiratory sounds is AUDIO-SPECTRUMANALYSIS™ or SPECTROGRAM VERSION 6™, shareware available fromVisualization Software, LLC which is downloadable over the Internet atvisualizationsoftware.com.

While the present invention is described herein with reference toillustrated embodiments, it should be understood that the invention isnot limited hereto. Those having ordinary skill in the art and access tothe teachings herein will recognize additional modifications andembodiments within the scope thereof. Therefore, the present inventionis limited only by the claims attached herein.

We claim:
 1. An apparatus for recording respiratory sounds of anexercising horse which comprises: (a) a microphone with a head whichdetects respiratory sounds at close proximity; (b) a horse restrainingapparatus comprising a nose-band and a cheek-piece with a top for goingbehind and around the ears of the horse which is mountable on the headof the horse and which includes a support means with a distal end and aproximal end wherein the microphone is securely mounted to the distalend of the support means and the proximal end of the support means issecurely mounted on the nose-band of the horse restraining apparatus andwherein the support means enables the head of the microphone to bepositioned between nostrils of the horse and without touching the horseso that the respiratory sounds at close proximity to the nostrils of thehorse are detected; and (c) a recording means for recording therespiratory sounds detected by the microphone at close proximity to thenostrils of the horse wherein the recording means squelches other soundsat a distance from the nostrils.
 2. The apparatus of claim 1 wherein awire for transmitting the respiratory sounds detected by the microphoneto the recording means extends from the microphone to the recordingmeans along a path which is parallel to the support means mounted on thenose-band of the horse restraining apparatus and is parallel to thenose-band and the cheek-piece to the top of the cheek-piece and whichextends from the top of the cheek-piece to the recording means.
 3. Theapparatus of claim 2 wherein the support means is a tube defined by atleast one wall forming the tube in which the wire for transmitting therespiratory sounds extends therethrough.
 4. The apparatus of claim 1, 2,or 3 wherein the microphone is unidirectional.
 5. The apparatus of claim1, 2, or 3 wherein the recording means has a compression circuit whichallows for a constant recording level of the sounds at close proximityto the nostrils of the horse.
 6. The apparatus of claim 1 wherein themicrophone includes a wireless transmitter for transmitting therespiratory sounds to a wireless receiver in the recording means.
 7. Theapparatus of claim 1 wherein the microphone includes a wirelesstransmitter for transmitting the respiratory sounds to a wirelessreceiver in a computer for analyzing the respiratory sounds in realtime.
 8. The apparatus of claim 1 wherein the horse restrainingapparatus is selected from the group consisting of cavessons, bridles,bitless bridles, and halters.
 9. A method for recording and analyzingrespiratory sounds of an exercising horse to detect an airway conditionwhich comprises: (a) providing an apparatus for analyzing respiratorysounds of an exercising horse which comprises: (1) a microphone with ahead which detects respiratory sounds at close proximity; (2) a horserestraining apparatus comprising a nose-band and a cheek-piece with atop for going behind and around the ears of the horse which is mountableon the head of the horse and which includes a support means with adistal end and a proximal end wherein the microphone is securely mountedto the distal end of the support means and the proximal end of thesupport means is securely mounted on the nose-band of the horserestraining apparatus and wherein the support means enables the head ofthe microphone to be positioned between nostrils of the horse andwithout touching the horse so that the respiratory sounds at closeproximity to the nostrils of the horse are detected; and (3) a recordingmeans for recording the respiratory sounds detected by the microphone atclose proximity to the nostrils of the horse and squelching other soundsat a distance from the nostrils; (b) mounting the apparatus on the headof the horse and positioning the head of the microphone to be adjacentto the nostrils of the horse; (c) recording the respiratory soundsdetected by the head of the microphone with the recording means; and (d)analyzing the respiratory sounds recorded on the recording means todetect the condition.
 10. The method of claim 9 wherein a wire fortransmitting the respiratory sounds detected by the microphone to therecording means extends from the microphone to the recording means alonga path which is parallel to the support means mounted on the nose-bandof the horse restraining apparatus and is parallel to the nose-band andthe cheek-piece to the top of the cheek-piece and which extends from thetop of the cheek-piece to the recording means.
 11. The method of claim10 wherein the support means is a tube defined by at least one wallforming the tube in which the wire for transmitting the respiratorysounds extends therethrough.
 12. The method of claim 9 wherein themicrophone includes a wireless transmitter for transmitting therespiratory sounds to a wireless receiver in the recording means. 13.The method of claim 9 wherein the microphone includes a wirelesstransmitter for transmitting the respiratory sounds to a wirelessreceiver in a computer for analyzing the respiratory sounds in realtime.
 14. The method of claim 9, 10, 11, 12, or 13 wherein the analysisis for laryngeal hemiplegia and dorsal displacement of the soft palate.15. The method of claim 9, 10, 11, 12, or 13 wherein a computer programproduces a graph of the respiratory sounds for analyzing in step (d).16. The method of claim 9 wherein the horse restraining apparatus isselected from the group consisting of cavessons, bridles, bitlessbridles, and halters.
 17. The method of claim 9, wherein the airwaycondition is an upper airway obstructive condition.